Swimming pool cleaning machines are known and largely adopted at present, which comprise a frame supported by driving means, e.g. an electric motor designed to drive a number of small wheels or tracks arranged to move the cleaning machine backward and forward on an inner surface of a swimming pool, and one or more inlet openings arranged to suck from the bottom of the machine, the whole assembly being arranged in a housing shell.
The driving means is tight sealed in the housing shell and generally electrically connected by means of an electric cable, preferably provided with a float, to power mains through a transformer or a low-tension power supply located near to the swimming pool.
Generally speaking, the electric motor also drives a pair of rotatable brushes having their axes of rotation parallel to one another and arranged at two opposite sides of the cleaning machine, i.e. one in front and the other at the rear of cleaning machine.
In bottom of the housing shell, i.e. the housing shell surface designed to be facing, in use, against the swimming pool surface to be cleaned, a plurality of inlet openings are formed, through which swimming pool water can be sucked. The water thus sucked drags impurities and debris with it, e.g. fungi, algae, scale pieces, etc., from which the swimming pool itself must be cleaned, without the need for the swimming pool to be emptied before proceeding to a cleaning operation thereof.
The inlet openings are connected to suction means and filtering means generally comprising a pump arranged to suck water to be cleaned through the inlet openings and to send it to a filtering bag arranged within the housing shell of the cleaning machine. After filtration through the filtering bag, any sucked water is discharged into the swimming pool.
However, cleaning machines at present available on the market have some drawbacks. First of all, conventional cleaning machines are unable effectively to remove limestone and “rust” accrued and attached to the swimming pool walls. Limestone and rust removal requires hard manual work by the operator, who after a cleaning operation by means of a cleaning machine has to remove manually any scales on the swimming pool walls by means of brushes and the use of chemicals.
The filtering bag is thus liable to became obstructed quite rapidly especially if leaves, wooden fragments or other polluting elements of substantial size with respect to the dimensions of the filtering bag or through openings thereof.
When limestone, rust algae and fungi are firmly attached to the swimming pool walls, the two rotary brushes of a cleaning machine are fully inadequate to insure that the swimming pool floor and walls are satisfactorily cleaned.
Moreover, the electric cable, which plunges into water from the outside of the swimming pool for supplying the cleaning machine, represents often a risk of current escape.